Plot Of Viscosity Research Articles

Вязкость магнитных жидкостей при различных концентрациях коллоидных частиц и температурах

In the paper we present experimental results concerning measurements of dynamic viscosity of magnetic colloidal fluids. Magnetic colloidal fluids consist of their carrier fluids and solid magnetite particles with 9-10 nm in size. In the experiment we use two types of magnetic fluids – a kerosene-based magnetic fluid (MF k ) and an undecane-based magnetic fluid (MF u ). They differ by a manufacturer and date of manufacture. Viscosity measurements were carried out by a capillary viscometer equipped with the sensors specially designed for this experiment. Sensors were made on the basis of copper-constantan thermocouples combined with a microvoltmeter and a clock. They allowed measuring the time needed for a control volume of magnetic fluid flows through a capillary of the viscometer. In the experiment we obtained an array of data on viscosity of the fluids MF k and MF u with magnetite particle volume fractions of 0, 6, 10, 13, 16 % at temperatures of 20, 30, 40, 50 °C. Plots of dynamic viscosity versus temperature were built. Viscosities of the magnetic fluids MF k and MF u were compared. It was found that a ratio of viscosity coefficients for these fluids does not depend on temperature in the temperature range considered. Viscosity coefficients of the fluids MF k and MF u also increase in a similar way as particle volume fractions goes up to 10%. If a particle volume fraction is more than 10%, viscosity of the fluid MF k significantly exceeds viscosity of the fluid MF u .

Comparative analysis of heat and mass transfer processes in the extruder dosing zone with the use of different spatial mathematical models and rheological law

At present, polymer compositions based on polyethylene or PVC are widely used as insulating materials. The processing of these materials is associated with a number of problems in the choice of rational processing modes. In order to minimize the time and cost necessary to determine a particular technological regime, methods of mathematical modeling are used. Development and analysis of various mathematical models of the flow and heat transfer in helical channels allows us to evaluate the possibility of using simplifying assumptions and their effect on flow pattern and process parameters during processing of polymeric materials in extrusion equipment. In this work, a three-dimensional model of flow and heat transfer processes in the dosing zone of a plasticizing extruder taking into account the clearance above the crest of the screw is developed, and the numerical study of a polymer melt flow in this zone is presented. The analysis of spatial mathematical models with different channel geometry (a rectangular channel deployed on plane and a screw channel having much in common with that used in the actual process of recycling) is carried out. The influence of assumptions of the inverted movement of the screw on the polymer melt flow character for the considered spatial models of heat and mass transfer process is evaluated. The effect of the clearance between the crest of the screw and the inner surface of the housing on the temperature distribution in the channel is investigated. Experimental plots of viscosity versus shear rate for the insulating polymer compositions are obtained and the empirical coefficients for the three rheological laws (power law, Kerry model and Crosse model) are determined. A numerical comparison of the calculation results obtained for this rheology models of polymer melt under complex shear in the extruder screw channel is performed. The values of maximum and medium temperature at the outlet of the channel and a comparison with the results obtained by other authors are given.

Cations/Anions Effects of Imidazolium-based Ionic Liquids on the Diffusion Properties of Iron- and Ruthenium-bipyridine/phenanthroline Complexes

The diffusion coefficients of both iron(II)-bipyridine ([Fe(bpy)3]2+), ruthenium(II)-bipyridine ([Ru(bpy)3]2+) are reported in five of different imidazolium-based ionic liquids (ILs) and iron(II)-phenanthroline ([Fe(phen)3]2+), ruthenium(II)-phenanthroline ([Ru(phen)3]2+) in one of imidazolium-based ionic liquid, using cyclic voltammetry and chronoamperometry at microdisc electrodes. Activation energies of diffusion, ED, are calculated for each system. Diffusion coefficient ratios between oxidation and reduction species for both complexes were found to be close to 1. Plots of diffusion coefficients versus inverse viscosity deviate from expected linearity, especially for ILs with different kind of anions, suggesting that anions of the ILs contribute to the values of diffusion coefficients. ED for both complexes in ILs are found slightly larger compared to the activation energies of viscous flow (Eη) for the corresponding IL, indicating that the viscosity is not the only factor determining the diffusion of the complexes. Furthermore, the hydrodynamic radius of complexes in ILs were estimated based on the diffusion coefficient values. They are found to be independent of temperature and ILs viscosity.

On limitations of the viscosity versus temperature plot for glass-forming substances

The plot scaling of viscosity by the reduced temperature as an important and vivid representation of the liquid fragility property has been utilized by materials scientists for more than four decades. In the present manuscript we discuss practical limitations on the high temperature part of the viscosity plot. It is valid up to the boiling point at pressure ranges from the triple point to the critical pressure and nearly up to the critical temperature at high pressure. Although, the high temperature viscosity estimation at T→∞ is rather a result of overestimation of an Arrhenius or VFTH equitation fitting and does not have a physical meaning more attention is required to shed light on the behavior of glass-forming liquids in this temperature range by taking into account the supercritical liquid phenomenon.

Ethylene Methyl Acrylate Copolymer Toughened Poly(lactic acid) Blends: Phase Morphologies, Mechanical and Rheological Properties

Abstract The ethylene methyl acrylate copolymer (EMA), for the first time, was melt blended with poly(lactic acid) (PLA) by a twin-screw extruder to toughen PLA. The phase morphologies, mechanical, and rheological properties of the PLA/EMA blends with six weight ratios were investigated. The results showed that the addition of EMA improves the toughness of PLA at the expense of the tensile strength, flexural strength and modulus to a certain degree, and results in the transition from brittle fracture of PLA into ductile fracture. The droplet-matrix morphology is observed in the PLA/EMA blends, in which the mean diameter of EMA droplets increases and its distribution widens gradually with increasing the EMA content. The PLA/EMA blends with three weight ratios (90/10, 80/20, and 70/30) display different characteristic linear viscoelastic properties in the low frequency region, which were investigated in terms of their complex viscosity, storage modulus, and Cole-Cole plots. The interfacial tension between the PLA and EMA is calculated using the Palierne model conducted on the 80/20 PLA/EMA blend, and the calculated result is 3.3 mN/m.

Effect of Isotacticity of Linear Poly(N-isopropylacrylamide) on its Gelation in Benzyl Alcohol

Thermoreversible gelation of three different isotactic linear poly(N-isopropylacrylamide) (PNIPAM)s having meso dyad (m) values 62, 68 and 81% has been observed in benzyl alcohol. All the gels were transparent in nature. SEM image of the dried gels showed fibrillar network morphology. Melting temperature of the gels gradually increased with the increase in the concentration. XRD data of dry polymers and their corresponding dry gels showed shifting in the peak positions. Rheological study showed that stronger gels were formed with increasing isotacticity of PNIPAM while lower isotactic sample exhibited typical polymer melt rheology. The formation of a plunge in the storage modulus as well as in the viscosity plot at the same frequency range indicates the reversible nature of the structure breaking/reformation under frequency sweep. Moreover, the mechanical strength of the gel decreased with increase in temperature. UV-Vis kinetic study also indicated the change in the conformation and aggregation of PNIPAM chains during gelation. Molecular modelling calculation showed that the number of solvent molecules involved in forming gel (polymer-solvent compound) decreased with the increase in the isotacticity of the polymer. Gelation rate of these gels was studied as a function of temperature, concentration and isotacticity using test-tube tilting method. It increased with the increase in the concentration and isoacticity of the polymer, and with the decrease in the temperature. Critical gelation concentration of the gel gradually increased with the decrease in the isotacticity and with the increase in the temperature. All these experimental results indicated that gelation occurs presumably through polymer-solvent compound formation. Thermoreversible gelation of different isotactic [meso diad (m) = 62, 68 and 81%] linear poly(N-isopropylacrylamide) (PNIPAM)s has been observed in benzyl alcohol. Gelation rate depends on temperature, concentration, and isotacticity of PNIPAM. SEM, XRD, rheology and UV-Vis studies, and molecular modelling support its formation presumably via polymer-solvent compound formation.

Effect of surfactant concentration on foam: From coreflood experiments to implicit-texture foam-model parameters

We present a comparative study of foam coreflood experiments with various surfactant concentrations. Plots of apparent viscosity vs. injected gas fraction were obtained for surfactant concentrations at the critical micelle concentration and above. Bulk foam stability was measured for all concentrations and compared with the coreflood results. There were different responses to surfactant concentration in bulk and in corefloods.The coreflood results were matched with an implicit-texture foam model, and the dependency of the model parameters on the surfactant concentration is discussed. Fitting the data requires relating the surfactant concentration to the dry-out function or the limiting capillary pressure.

Characterization of Low-Density Polyethylene in Dibutoxymethane by High-Temperature Gel Permeation Chromatography with Triple Detection

The study presents the possibility to replace the 1,2,4-trichlorobenzene (TCB) for the analysis by gel permeation chromatography (GPC) of low-density polyethylenes (LDPE) with dibutoxymethane (DBM, butylal), a halogen free and less toxic solvent. The molecular weight distributions and the viscosity plots were measured for commercial LDPE samples solubilized in TCB, and DBM, using a GPC system with triple detection (light scattering, differential refractive index and viscometer). Similar results were obtained in both solvents for the molecular weight and long chain branching distributions of the analyzed resins, thus confirming the possibility to replace TCB with DBM for the analysis by high-temperature GPC of all types of polyolefins.

Study of Magnetoviscosity of Ferromagnetic MnZn-Ferrite Ferrofluid

Mn0.75Zn0.25Fe2O4 (MZF) ferrofluid was synthesized with oleic acid-coated MZF nanoparticles dispersed in toluene (less viscous fluid). The Rietveld refinement for the X-ray diffraction pattern of MZF nanoparticles showed the single phase spinel structure formation with Fd-3m space group. The nanophase and the particle size distribution of MZF nanoparticles (7–15 nm) were observed on transmission electron micrograph. The soft ferrimagentic behavior can be observed from the magnetization versus applied magnetic field ( $H$ ) plots at 325 and 5 K. The power law behavior is verified for shear rate versus viscosity plots at various magnetic fields. The power index $(n)$ value decreases from 0.1 to 0.04 with increase in magnetic field from 0 to 1.33 T. The low $n$ -value indicates non-Newtonian behavior shear thinning for the ferrofluid at various applied magnetic fields. The Herschel–Bulkley model fit is verified for shear stress versus shear rate. The yield stress values were obtained by extrapolating the experimental shear stress versus shear rate plots to zero shear rate. The ferromagnetic nanoparticles (magnetic dipole particles) of ferrofluid rotate in the direction of magnetic field with the increase in field. Above certain magnetic field $(>0.2~{\rm T})$ , the magnetic field effect dominates other effects present in the fluid. This is due to long chain formation perpendicular to the shear flow field in the ferrofluid. We also discuss the dependence of viscosity and shear stress on applied magnetic field from magnetoviscosity plots at constant shear rates.

Melt rheology of poly(vinylidene fluoride) (PVDF)/low density polyethylene (LDPE) blends

The aim of this work is to study the rheological properties of PVDF/LDPE blends in the molten state, in relation to shear rate, shear stress and temperature. Blends of LDPE and PVDF at different compositions, namely PVDF/LDPE = 0/100, 30/70, 50/50, 70/30, 100/0 were realized. The blends were prepared by using brabender plastograph and measurements were carried out by using capillary rheometer. For studying the viscous properties non-Newtonian index n, true viscosity η and the flow activation energy E were determined. The melt elasticity has been studied in term of die swell ratio B. The results show that PVDF/LDPE blends behave in pseudo-plastic manner (n < 1), plots of true viscosity versus blending ratio go through a minimum nearly at blending ratio (50/50), and the flow activation energy decreases with increasing shear rate at the wall γ but it increases with increasing true shear stress τ. The results of die swell ratio show that, B increases linearly with increasing true shear stress τ, while B decreases with increasing L/R. It was also found that a maximum of elastic properties is observed at certain blending ratio. This phenomenon can be attributed to the amount of elastic deformation energy stored in the melt flow and its transition due to the viscoelastic difference between the two phases.

Mixing Analysis in a Stirred Tank Using Computational Fluid Dynamics

In this study computational fluid dynamics (CFD) approach was used to study mixing in an Industrial gold leaching tank. The objective was to analyze the extent of mixing in the tank by producing visual images of the various mixing zones in the tank domain. Eddy viscosity plots that characterise the extent of mixing in the tank were generated in the flow field obtained by an Eulerian-Eulerian approach. The extent of mixing was found to be greatest in the circulation loops of the impeller discharge region and least at the top and bottom portions of the tank. Trailing vortices that contribute to some level of mixing were identified in between the impeller blades. This approach could be used to enhance optimum design of mixing vessels and to eliminate the need for pilot plants.

Recycling of acrylonitrile–butadiene–styrene (ABS) copolymers from waste electrical and electronic equipment (WEEE), through using an epoxy-based chain extender

The effect of adding an epoxy-based chain extender (CE) on the properties of recycled acrylonitrile–butadiene–styrene (rABS) copolymers has been studied. At the beginning of this work, we investigated the difference of properties between rABS and virgin ABS, and then a possible aging mechanism was proposed. Various characterization techniques including attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, gel permeation chromatography (GPC), mechanical properties testing and dynamic mechanical analysis (DMA), rheological measurement, and scanning electron microscopy (SEM) were applied to study the modification of chemical structure, molecular weight, mechanical properties, dynamic mechanical properties, rheological properties and morphology, respectively. The results indicated that the molecular weight, notch impact strength and tensile strength, storage modulus and loss modulus, and complex viscosity of rABS were enhanced by the addition of CE. Furthermore, the complex viscosity plots also revealed that the chain-extended rABS (rABS-CE) had a branching structure which furnished a better utilization and processing properties to rABS for recycling.

Effect of carbamazepine on viscoelastic properties and hot melt extrudability of Soluplus®

The purpose of this study was to apply viscoelastic properties of polymer and drug-polymer mixtures to determine processing conditions for the preparation of amorphous solid dispersion by melt extrusion. A poorly water-soluble drug, carbamazepine (CBZ), was mixed with Soluplus® as the carrier. Torque analysis using a melt extruder was performed at 10, 20 and 30% w/w drug concentrations and the effect of barrel temperature was studied. Viscosity of the mixtures either at fixed temperatures with different angular frequencies or as a function of temperature with the same frequency was studied using a rheometer. The viscosity of Soluplus® and the torque exerted on the twin screws decreased with the increase in CBZ concentration. The viscosity versus temperature plots for different CBZ concentrations were parallel to each other, without the drug melting transition, indicating complete drug-polymer miscibility. Thus, the drug-polymer mixtures could be extruded at temperature as low as 140°C with 10% w/w drug load, 135°C with 20% w/w drug and 125°C with 30% w/w drug, which were, respectively, ∼50°C, 55°C and 65°C below the melting point of 191°C for CBZ. The differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD) analyses of the binary mixtures extruded at 125–150°C showed absence of crystalline drug. A systematic study of miscibility and extrudability of drug-polymer mixtures by rheological and torque analysis as a function of temperature will help formulators select optimal melt extrusion processing conditions to develop solid dispersions.

Rheological behaviour of clay incorporated natural rubber and chlorobutyl rubber nanocomposites

The rheological behaviour of organoclay nanocomposites based on natural rubber (NR) and chlorine substituted isobutyl-isoprene rubber (CIIR), was investigated separately. For the study, an organoclay Nanomer I.44P treated with a surfactant containing hydrogenated tallow, quaternary ammonium chloride, was used. The linear dynamic viscoelastic measurements indicated that the viscosity of NR/organoclay nanocomposites increased as the nanofiller content increases from 0 to 10 phr. NR nanocomposites showed the network formation, however, real solid like behaviour was not observed as reported in the case of other polymer/clay nanocomposites. The extent of exfoliation of nanofillers in NR nanocomposites was estimated using their shear thinning behaviour. Form factor calculations based on TEM data indicated excellent dispersion of clay in the NR matrix. The modeling of the linear dynamic viscoelasticity in NR nanocomposites has been done using the Carreau–Yasuda model (CY model). Interestingly, the behaviour of CIIR nanocomposites was very different from NR nanocomposites. CIIR/organoclay nanocomposites did not show any variation in the viscosity as the filler loading varies from 0 to 10 phr. Viscosity and modulus plots as a function of frequency with varying clay content coalesced into a master curve indicating lack of interaction between clay and CIIR matrix. This has been explained based on polarity mismatch, steric effects and high viscosity of CIIR as compared to NR. The WAXD and TEM analyses showed an intercalated and agglomerated morphology for CIIR/clay nanocomposites. The behaviour of CIIR nanocomposites in this study has been explained by suggesting a different mechanism, where nanofillers are encapsulated in certain “pockets”. The mechanism proposed on CIIR nanocomposites is supported with the help of transmission electron microscopy (TEM).

Viscosity-Temperature Behavior of Hydroxypropyl Cellulose Solution in Presence of an Electrolyte or a Surfactant: A Convenient Method to Determine the Cloud Point of Polymer Solutions

The viscosity of hydroxypropyl cellulose (HPC) solution with or without an additive has been measured continuously as a function of temperature with the help of a vibro-viscometer. The viscosity of the polymer solution showed a gradual decrease initially with increase in temperature until a particular point beyond which there was a sharp decrease in the viscosity, which coincided with the clouding of the solution. The cloud point temperature (CP) of the polymer solution was determined from the first derivative plot of viscosity vs. temperature. Effect of addition of an electrolyte or a surfactant on the CP of HPC solution has also been studied. While a decrease in CP of HPC solution in presence of fluoride, chloride, or bromide ions was observed, presence of iodide or thiocyanide ions led to an increase in the CP. However, presence of an ionic surfactant initially lowered the CP but beyond a particular surfactant concentration a sharp increase in cloud point was observed due to interaction of the surfactant with the polymer. The results suggest that surfactants with longer hydrophobic tail or more hydrophobic groups have more affinity for HPC.

The thermotropic liquid crystalline behavior of mesophase pitches with different chemical structures

Chemical structure-dependent liquid crystalline behaviors of two commercial mesophase pitches, M-AR and T-MP, which are synthesized with different raw materials of naphthalene and coal tar, respectively, were comparatively examined. The NMR analysis together with preparation procedure enabled us to suggest that M-AR consisted of linear semi-rigid molecules and T-MP, irregularly shaped rigid molecules. Between 320 and 370°C M-AR showed marbled texture whereas T-MP, a change from schlieren/marbled to schlieren texture. WXRD results indicated that M-AR exhibited a gradual change of d002 and Lc with temperature but T-MP, a drastic change. A point shear stress made M-AR produce oriented flow domains but T-MP retained schlieren texture even in the oriented structure. In the temperature range producing biphase, M-AR showed a shoulder on the plot of viscosity versus temperature but T-MP, a peak. As temperature was increased M-AR gave an increase of loss tangent but a decrease of yield stress while T-MP gave a saturation point at 330°C, at which temperature loss tangent was maximum and yield stress was minimum. Both mesophase pitches gave viscosity curves matched with the Asada–Onogi model. In the temperature range producing dispersed polydomain system, however, T-MP showed almost shear rate-independent plateau while shear-dependence was observed in M-AR.

Physicochemical Properties of Nonvariant Compositions of Ternary NaF-LiF-LnF3 Systems (Ln = La, Nd)

This paper presents results of investigations of the physicochemical properties of nonvariant compositions of ternary NaF-LiF-LnF3 systems (Ln = La, Nd) in crystalline-molten transition. The investigations have been carried out by differential thermal and X-ray phase analysis, high-temperature X-ray diffractometry, viscosimetry and thermal emf method.The ternary system NaF-LiF-LaF3 has two nonvariant points: eutectic and peritectic. The eutectic mixture of this system has the composition (mol.%): NaF(44.0)–LiF(42.0)–LaF3(14.0) and melts at 580±2°C. The peritectic has the composition (mol.%): NaF(45.0)–LiF(39.0)–LaF3(16.0) and melts at 595±2°C. Unlike the foregoing system, the ternary system NaF–LiF–NdF3 has one eutectic and two peritectics. The eutectic has the composition (mol.%): NaF(33.0)–LiF(53.0)–NdF3(14.0) and melts at 580±2°C. The peritectic, which corresponds to the formation of the compound NaNdF4, has the composition (mol.%): NaF(41.0)–LiF(44.0)– NdF3(15.0) and a melting point 595±2°C. The second peritectic has the composition (mol.%): NaF(39.0)–LiF(45.0)– NdF3(16.0) and melts at 610±2°C.An analysis of the results obtained showed that before reaching the melting temperature, the eutectic compositions of the investigated systems do not undergo structural and phase transformations. Above the melting temperature, the structure of eutectic melts is different in sprite of the very close ionic radii of rare-earth cations (rLa = 0.103 nm, rNd = 0.098 nm) and equal charges. The basis of the eutectic melt structure of the ternary LiF-NaF-LaF3 system in the range 580-700 0C is a fluoride matrix, formed by complex LaF6 3- anions. The fluorine ions around the lanthanum ions form a deformed trigonal Bernal prism. The alkali metal cations are chaotically arranged in the fluoride matrix. In the LiF-NaF-NdF3system, the fluorine ions do not form a homogeneous matrix; the melt is structurally inhomogeneous, and the neodymium cations do not form locally ordered centers with lithium and sodium polyhedra attached to them.It has been found that the plots of thermoelectric coefficient against temperature for each of the investigated nonvariant compositions have a certain temperature T, at which their slope changes its sign from negative to positive. This temperature is about 120-160°C higher than the melting temperature of the corresponding nonvariant compositions and depends on the mode of interaction of the original reactants and the nature of the compounds that are formed in this case. The reversal of the sign of the plot of thermal emf against temperature may indicate that the nature of charge carriers changes at certain temperatures.The structural inhomogeneity of the investigated compositions of the above ternary systems in the molten state is also evidenced by the results of viscosimetric studies (method of damped torsional vibration of cylinder). It has been found that as in the foregoing case, a certain characteristic temperature is typical of each of studied compositions, at which the slope of the temperature plot is reversed. Above this temperature, the plot of viscosity against temperature is satisfactorily approximated by the Arrhenius equation. This dependence of viscosity on temperature is likely due to dynamics of incongruent melting of the binary compounds NaLaF4, NaNdF4 and Na5Nd9F32.The identified characteristic temperatures on the plots of viscosity against temperature as well as on plots of coefficient of thermoelectric power against temperature increase in going from eutectic to peritectic compositions. Detected characteristic temperatures can be a sort quantitative measure of termination of incongruent decomposition of binary compounds NaLaF4, NaNdF4 and Na5Nd9F32.

Magneto-viscosity of MnZn-ferrite ferrofluid

Mn0.75Zn0.25Fe2O4 (MZF) ferrofluid was synthesized using a precipitation method in ethylene glycol colloidal media. The x-ray diffraction and transmission electron microscope studies show nanophase of the MZF ultra fine nanoparticles. The magnetization (M) vs magnetic field (H) show zero coercivity and high saturation field characteristic of superparamagnetic behavior. The dynamic light scattering (DLS) data show the formation of aggregates or clusters with size distribution ranging from 50 to 600nm. Magneto-viscosity of the ferrofluid is studied using rheological measurements under magnetic field up to 1.3T. The behavior of shear rate vs effective shear viscosity (η) plot in zero and higher magnetic field changes from non-Newtonian to Newtonian as shear rate increases. At a steady shear rate irreversible nonlinear behavior is observed in η vs H plots. The data indicate the particle size distribution and formation of chains in the ferrofluid with increase in magnetic field.

The effect of the intimate structure of the solid binder on material viscosity during drum granulation

The effect of the structure of the solid binder on material viscosity during drum granulation was investigated it was found that nucleation was the most important step in the wet granulation process, but the rate of nucleation was determined by the viscosity of the fertilizer material, through the study of the surface structure of calcium carbonate, coarse whiting, attapulgite, desulfurization gypsum powders, and different binder content versus viscosity plots. The results showed that the adsorption ability of calcium carbonate, the formation of the water film of attapulgite, and the production of whiskers of desulfurization gypsum influenced the fertilizer material's viscosity and granulation. Meanwhile the work provided a theoretical basis for the study of the mechanism of nucleation.

Quantitative correlation between counterion (X) binding affinity to cationic micelles and X – Induced micellar growth for substituted iodobenzoates (X)

A new semi-empirical kinetic (SEK) method has been used to calculate the values of KXBr or RXBr (X represents substituted iodobenzoates), with KX and KBr representing CTABr micellar binding constants of counterions X− (in the presence of either spherical or non-spherical micelles) and Br− (in the presence of only spherical micelles), respectively. Steady-shear rheological properties of mixed 0.015M CTABr/[MX] aqueous solutions reveal the presence of flexible wormlike micelles where MX represents sodium 3- and 4-iodobenzoates. The maxima of the plots of viscosity vs. [MX] at 0.015M CTABr for MX representing sodium 3- and 4-iodobenzoates support the presence of long linear and entangled wormlike micelles.